插入新游戏时出现Symfony错误：必须管理传递给选择字段的实体 . 也许坚持他们在实体经理？

我正在尝试使用Type对象保存Game对象 . 当我尝试使用表单保存时，我收到以下错误：

必须管理传递到选择字段的实体 . 也许坚持他们在实体经理？

一个游戏可以有1个类型，而类型可以有多个游戏 .

我设法隔离了这个问题，当Game与Type没有关系时它工作正常，所以我认为它必须对Type对象做一些事情 .

GameController：

<?php

namespace AppBundle\Controller;

use AppBundle\Entity\Game;
use AppBundle\Entity\Type;
use Symfony\Bundle\FrameworkBundle\Controller\Controller;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Method;
use Sensio\Bundle\FrameworkExtraBundle\Configuration\Route;
use Symfony\Component\HttpFoundation\Request;

/**
 * Game controller.
 *
 * @Route("game")
 */
class GameController extends Controller
{
    /**
     * Lists all game entities.
     *
     * @Route("/", name="game_index")
     * @Method("GET")
     */
    public function indexAction()
    {
        $em = $this->getDoctrine()->getManager();

        $games = $em->getRepository('AppBundle:Game')->findAll();

        return $this->render('game/index.html.twig', array(
            'games' => $games,
        ));
    }

    /**
     * Creates a new game entity.
     *
     * @Route("/new", name="game_new")
     * @Method({"GET", "POST"})
     */
    public function newAction(Request $request)
    {

        $type = new Type();
        $game = new Game();
        $game->setType($type);

        $form = $this->createForm('AppBundle\Form\GameType', $game);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            $em = $this->getDoctrine()->getManager();
            $em->persist($type);
            $em->persist($game);
            $em->flush($game);

            return $this->redirectToRoute('game_show', array('id' => $game->getId()));
        }

        return $this->render('game/new.html.twig', array(
            'game' => $game,
            'form' => $form->createView(),
        ));
    }

    /**
     * Finds and displays a game entity.
     *
     * @Route("/{id}", name="game_show")
     * @Method("GET")
     */
    public function showAction(Game $game)
    {
        $deleteForm = $this->createDeleteForm($game);

        return $this->render('game/show.html.twig', array(
            'game' => $game,
            'delete_form' => $deleteForm->createView(),
        ));
    }

    /**
     * Displays a form to edit an existing game entity.
     *
     * @Route("/{id}/edit", name="game_edit")
     * @Method({"GET", "POST"})
     */
    public function editAction(Request $request, Game $game)
    {
        $deleteForm = $this->createDeleteForm($game);
        $editForm = $this->createForm('AppBundle\Form\GameType', $game);
        $editForm->handleRequest($request);

        if ($editForm->isSubmitted() && $editForm->isValid()) {
            $this->getDoctrine()->getManager()->flush();

            return $this->redirectToRoute('game_edit', array('id' => $game->getId()));
        }

        return $this->render('game/edit.html.twig', array(
            'game' => $game,
            'edit_form' => $editForm->createView(),
            'delete_form' => $deleteForm->createView(),
        ));
    }

    /**
     * Deletes a game entity.
     *
     * @Route("/{id}", name="game_delete")
     * @Method("DELETE")
     */
    public function deleteAction(Request $request, Game $game)
    {
        $form = $this->createDeleteForm($game);
        $form->handleRequest($request);

        if ($form->isSubmitted() && $form->isValid()) {
            $em = $this->getDoctrine()->getManager();
            $em->remove($game);
            $em->flush($game);
        }

        return $this->redirectToRoute('game_index');
    }

    /**
     * Creates a form to delete a game entity.
     *
     * @param Game $game The game entity
     *
     * @return \Symfony\Component\Form\Form The form
     */
    private function createDeleteForm(Game $game)
    {
        return $this->createFormBuilder()
            ->setAction($this->generateUrl('game_delete', array('id' => $game->getId())))
            ->setMethod('DELETE')
            ->getForm()
        ;
    }
}

GameType.php：

<?php
namespace AppBundle\Form;
use Symfony\Component\Form\Extension\Core\Type\TextType;
use Symfony\Bridge\Doctrine\Form\Type\EntityType;
use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class GameType extends AbstractType
{
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder
            ->add( 'name', TextType::class);
        $builder
            ->add( 'type', EntityType::class, [
                'class' => 'AppBundle:Type',
                'choice_label' => 'name',
                'multiple' => false,
                'expanded' => false
            ] );


    }

    /**
     * {@inheritdoc}
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'AppBundle\Entity\Game'
        ));
    }

    /**
     * {@inheritdoc}
     */
    public function getBlockPrefix()
    {
        return 'appbundle_game';
    }


}

TypeType.php

<?php

namespace AppBundle\Form;

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

class TypeType extends AbstractType
{
    /**
     * {@inheritdoc}
     */
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        $builder->add('name')        ;
    }

    /**
     * {@inheritdoc}
     */
    public function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults(array(
            'data_class' => 'AppBundle\Entity\Type'
        ));
    }

    /**
     * {@inheritdoc}
     */
    public function getBlockPrefix()
    {
        return 'appbundle_type';
    }


}

Game.php：

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\ArrayCollection;


/**
 * Game
 *
 * @ORM\Table(name="game")
 * @ORM\Entity(repositoryClass="AppBundle\Repository\GameRepository")
 */
class Game
{
    /**
     * @ORM\ManyToOne(targetEntity="Type", inversedBy="games")
     * @ORM\JoinColumn(name="type_id", referencedColumnName="id")
     */
    private $type;



    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;


    /**
     * @var string
     *
     * @ORM\Column(name="name", type="string", length=255, unique=true)
     */
    private $name;


    /**
     * Get id
     *
     * @return int
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * Set name
     *
     * @param string $name
     *
     * @return Game
     */
    public function setName($name)
    {
        $this->name = $name;

        return $this;
    }

    /**
     * Get name
     *
     * @return string
     */
    public function getName()
    {
        return $this->name;
    }

    /**
     * @return mixed
     */
    public function getType()
    {
        return $this->type;
    }

    /**
     * @param mixed $type
     */
    public function setType($type)
    {
        $this->type = $type;
    }



}

Type.php

<?php

namespace AppBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Doctrine\Common\Collections\ArrayCollection;


/**
 * Type
 *
 * @ORM\Table(name="type")
 * @ORM\Entity(repositoryClass="AppBundle\Repository\TypeRepository")
 */
class Type
{
    /**
     * @ORM\OneToMany(targetEntity="Game", mappedBy="type")
     */
    private $games;

    public function __construct()
    {
        $this->games = new ArrayCollection();
    }
    /**
     * @var int
     *
     * @ORM\Column(name="id", type="integer")
     * @ORM\Id
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    private $id;

    /**
     * @var string
     *
     * @ORM\Column(name="name", type="string", length=255)
     */
    private $name;




    /**
     * Get id
     *
     * @return int
     */
    public function getId()
    {
        return $this->id;
    }

    /**
     * Set name
     *
     * @param string $name
     *
     * @return Type
     */
    public function setName($name)
    {
        $this->name = $name;

        return $this;
    }

    /**
     * Get name
     *
     * @return string
     */
    public function getName()
    {
        return $this->name;
    }

/**
 * @return mixed
 */
public function getGames()
{
    return $this->games;
}

/**
 * @param mixed $games
 */
public function setGames($games)
{
    $this->games = $games;
}

public function addGame(Game $game)
{
    $this->games->add($game);
    $game->setType($this);
}
public function removeGame(Game $game)
{
    $this->games->removeElement($game);
}


}

游戏/ new.html.twig：

{% extends 'base.html.twig' %}

{% block content%}
    <h1>Game creation</h1>

    {{ form_start(form) }}
        {{ form_widget(form.name) }}
        {{ form_widget(form.type) }}
        <input type="submit" value="Create" />
    {{ form_end(form) }}

    <ul>
        <li>
            <a href="{{ path('game_index') }}">Back to the list</a>
        </li>
    </ul>
{% endblock %}